/*字体大小控制*/
!function (win, lib) {
    var timer,
            doc = win.document,
            docElem = doc.documentElement,
            vpMeta = doc.querySelector('meta[name="viewport"]'),
            flexMeta = doc.querySelector('meta[name="flexible"]'),
            dpr = 0,
            scale = 0,
            flexible = lib.flexible || (lib.flexible = {});

    // 设置了 viewport meta
    if (vpMeta) {
        var initial = vpMeta.getAttribute("content").match(/initial\-scale=([\d\.]+)/);

        if (initial) {
            scale = parseFloat(initial[1]); // 已设置的 initialScale
            dpr = parseInt(1 / scale);      // 设备像素比 devicePixelRatio
        }
    }
    // 设置了 flexible Meta
    else if (flexMeta) {
        var flexMetaContent = flexMeta.getAttribute("content");
        if (flexMetaContent) {

            var initial = flexMetaContent.match(/initial\-dpr=([\d\.]+)/),
                    maximum = flexMetaContent.match(/maximum\-dpr=([\d\.]+)/);

            if (initial) {
                dpr = parseFloat(initial[1]);
                scale = parseFloat((1 / dpr).toFixed(2));
            }

            if (maximum) {
                dpr = parseFloat(maximum[1]);
                scale = parseFloat((1 / dpr).toFixed(2));
            }
        }
    }

    // viewport 或 flexible
    // meta 均未设置
    if (!dpr && !scale) {
        var u = (win.navigator.appVersion.match(/android/gi), win.navigator.appVersion.match(/iphone/gi)), _dpr = win.devicePixelRatio;
        dpr = u ? ((_dpr >= 3 && (!dpr || dpr >= 3)) ? 3 : (_dpr >= 2 && (!dpr || dpr >= 2)) ? 2 : 1) : 1;
        scale = 1 / dpr;
    }

    docElem.setAttribute("data-dpr", dpr);

    // 插入 viewport meta
    if (!vpMeta) {
        vpMeta = doc.createElement("meta");

        vpMeta.setAttribute("name", "viewport");
        vpMeta.setAttribute("content",
                "initial-scale=" + scale + ", maximum-scale=" + scale + ", minimum-scale=" + scale + ", user-scalable=no");

        if (docElem.firstElementChild) {
            docElem.firstElementChild.appendChild(vpMeta)
        } else {
            var div = doc.createElement("div");
            div.appendChild(vpMeta);
            doc.write(div.innerHTML);
        }
    }

    function setFontSize() {
        //var d=E.getBoundingClientRect().width;d/B>540&&(d=540*B);var e=d/10;E.style.fontSize=e+"px",z.rem=J.rem=e
        var winWidth = docElem.getBoundingClientRect().width;
        if (winWidth / dpr > 540) {
            (winWidth = 540 * dpr);
        }

        // 根节点 fontSize 根据宽度决定
        var baseSize = winWidth / 10;

        docElem.style.fontSize = baseSize + "px";
        flexible.rem = win.rem = baseSize;
    }

    // 调整窗口时重置
    win.addEventListener("resize", function () {
        clearTimeout(timer);
        timer = setTimeout(setFontSize, 300);
    }, false);

    // orientationchange 时也需要算下
    win.addEventListener("orientationchange", function () {
        clearTimeout(timer);
        timer = setTimeout(setFontSize, 300);
    }, false);

    // pageshow
    // keyword: 倒退 缓存相关
    win.addEventListener("pageshow", function (e) {
        if (e.persisted) {
            clearTimeout(timer);
            timer = setTimeout(setFontSize, 300);
        }
    }, false);

    // 设置基准字体
    if ("complete" === doc.readyState) {
        doc.body.style.fontSize = 12 * dpr + "px";
    } else {
        doc.addEventListener("DOMContentLoaded", function () {
            doc.body.style.fontSize = 12 * dpr + "px";
        }, false);
    }

    setFontSize();

    flexible.dpr = win.dpr = dpr;

    flexible.refreshRem = setFontSize;

    flexible.rem2px = function (d) {
        var c = parseFloat(d) * this.rem;
        if ("string" == typeof d && d.match(/rem$/)) {
            c += "px";
        }
        return c;
    };

    flexible.px2rem = function (d) {
        var c = parseFloat(d) / this.rem;
        if ("string" == typeof d && d.match(/px$/)) {
            c += "rem";
        }
        return c;
    }
}(window, window.lib || (window.lib = {}));
